The present invention relates to thermally insulating packaging. More particularly, the present invention relates to an improved method and apparatus for a packaging system with improved insulating, storage and cost effectiveness characteristics for transporting perishables and the like.
Over the last few years, the demand for edible perishables has dramatically increased. The well publicized health benefits of fresh edibles has fueled even greater growth in the demand for such products. Due to the nature of these fresh food products and the desire for off-season supply among consumers, it is frequently necessary to ship such products from remote locations to virtually every corner of the world.
The shipment or transport of perishable goods frequently requires that such materials remain at a stable temperature, which is either elevated or decreased with respect to ambient temperatures to which the packaging is exposed. Because of long transport times for perishable items and the sensitivity of certain of these items due to slight temperature fluctuations, considerable efforts have been made to provide shipping containers with improved insulating characteristics. Despite the at times satisfactory results of these prior art devices, they have likewise presented a number of drawbacks.
By far the most common material utilized in corrugated containers as an insulating packaging material has been expanded polystyrene (EPS) foam, which is commonly referred to as "styrofoam.RTM.". Although EPS has proven to possess acceptable insulating characteristics as a liner inside a corrugated box, for the shipment of perishable goods, use of this material has also required a number of compromises. To begin with, most packaging systems that use EPS liners have required a relatively thick liner of approximately 1 inch. Due to the thickness and density of the EPS materials they add weight to the packaging and increase freight costs while their cushioning effect in the overall packaging system is limited. The EPS liner therefore consumes a significant amount of space that could otherwise be utilized to ship a greater quantity of product.
Leakage from such a container is highly undesirable and can lead to degradation of the container material, weakening of its structural integrity and damage to the transporting aircraft or surface vehicle. Therefore, it is necessary that the EPS liner be formed in such a manner that the chances of such leakage occurring would be minimized. The joining of flat panels of polystyrene by gluing or other means has proven to be relatively ineffective and subject to separation upon jarring of the container. Molding of the EPS to a single piece liner again introduces additional cost, is not very flexible in terms of varying the size or thickness of the EPS liner. Such molding further requires substantial capital expenditure for each die mold needed to form EPS liners.
In addition, whether stored as flat panels or a molded container, the EPS liners require significant amounts of storage space. Since these liners are generally placed in corrugated type cartons, the user is left with a situation where the corrugated boxes are completely collapsible and can be stored flat and in large numbers without taking up much space, whereas the opposite is true for the EPS liners.
Due to the drawbacks presented by the EPS packaging system, substantial efforts have been directed to providing thermally insulated packaging without the use of an EPS liner. U.S. Pat. No. 4,889,252 to Rockom et al discloses the bonding of bubble-type insulation to an inner surface of a corrugated paper box. Because of the direct contact of the bubble-type insulation with the box, much of the potential thermal containment ability of the insulation is subject to being undermined by the conduction of temperatures through the insulation to or from the box and subsequently to or from the ambient atmosphere. Additionally, the box of Rockom is not fully collapsible once the insulation is bonded thereto. Many other recent efforts have been directed at attempting to substitute alternative packaging systems for the EPS liner.
While some of these systems provide arguably comparable insulating results, they frequently are cumbersome, costly, increase the weight of the overall package and decrease the volume of materials that can be transported in a given container. For example, U.S. Pat. No. 5,314,087 to Shea discloses a thermal reflective packaging system that requires at least one spacer insert between an outer and inner container, as well as a spacer tray. Additionally, the pouch of Shea requires a layer of single or double-bubble radiant barrier material to be sealed within a vinyl pouch in an expensive and time consuming procedure.
A number of other known designs have attempted to utilize a bag constructed to nest inside a corresponding corrugated or other outer container. Such bag type constructions have generally not followed the contours of the outer container and have frequently had poor insulating characteristics. As a result, they have generally been either too large or too small for the usually rectangular container that they have been put inside of. As a result, they have often ended up bunched up at the bottom or area location with unwanted excess material at each end wasting productive packing space and adding packaging weight and thereby increasing shipping costs. Likewise, if the bags are significantly smaller than the outer container that they are in, significant packing space is again wasted.
Attempting to consistently vary the size of such bags to match their contents is again another costly and cumbersome experience. In addition, the performance of any insulating container degrades in direct proportion to how tight the container is sealed. Prior art bags have had problems particularly when a liquid was inside of the bag in providing an adequate moisture-proof seal and preventing spillage. Damage to the outer container and/or the material inside the bags frequently resulted. Furthermore, many prior art designs have been designed to perform optimally only when they are not fully loaded with perishable items.
It is therefore apparent that there exists a need in the art for an improved packaging method and apparatus for perishable materials that provides a highly insulative packaging structure that is light weight, less costly for storage and shipping purposes, easily conforms to the shape of an outer shipping container fully collapsible and has thermal characteristics at least as good as EPS in most applications.